The invention relates to a method of encapsulating an electronic component consisting in that, after having fixed and electrically connected an active device to metallic conductors, at least one coating step is carried out by means of a synthetic resin, the conductors emerging partly from this coating.
The large majority of the electronic components and more particularly the semiconductor components require a protection of the active element, which could not operate satisfactorily while being continuously exposed to a non-controlled environment. Thus, the components generally comprise a protection envelope, which also permits of providing a standarized arrangement of the conductors in the form of output pins having dimensions and relative distances chosen among standardized values.
In certain cases, it is ensured that the electronic components are encapsulated in envelopes of the metallic and/or ceramic type, while these envelopes can be closed by the use of electric soldering, brazing or soft glass fusion. However, the techniques of this type are necessarily expensive so that they are rather reserved for products which must be capable of resisting very heavy environmental loads.
In the other cases, more generally use can be made of methods of encapsulation in which a step of coating with a synthetic resin is carried out and which consists most frequently in that the resin is moulded around the active component which resin constitutes after solidification the envelope of the component, of which the conductors partly enclosed by the resin emerge, however, to the exterior with respect to the subsequent electrical connection.
Apart from the optoelectronic components, the semiconductor devices have to be protected from the ambient light in order to avoid the production of undesirable photo-currents during operation. Therefore, these devices require an encapsulation by a resin opaque to light.
On the contrary, the optoelectronic devices, such as light-emitting diodes, photodiodes, phototransistors and photocouplers, require an encapsulation which is at least partly transparent to the radiation for which the device is designed to operate, either with respect to the exterior of the envelope of solely in the internal part of the device, in which an optical coupling is obtained (case of photocouplers).